The technical field of the present invention is that of slipping driving bands fitted to projectiles of any caliber fired from a rifled barrel.
In order to stabilize a projectile in its trajectory, use is made either of the gyroscopic effect or of fins.
The gyroscopic effect requires the projectile to be given a substantial spin during firing, this spin being provided by the barrel of the weapon which is heavily rifled.
Fin stabilization is obtained by means of fins projecting to the rear of the projectile thus generating a counter-torque in the trajectory. This type of projectile is fired either from rifled barrels or from smooth bore barrels. This type of stabilization is used essentially for ammunition the effect of which is chemical (hollow charge rounds) or kinetic (discarding-sabot rounds).
To allow this type of projectile to be fired from rifled barrels, engineering designs having been developed by different countries including France. The concept most frequently used is based essentially on limiting the spin of the projectile during the firing phase by means of a so-called slipping driving band which follows the rifling in the barrel while imparting only a slight spin to the projectile through a sliding friction. The concept of the slipping driving band is the one most often used for firing kinetic energy rounds of the discarding sabot type from rifled barrels.
Reference will be made for example to patent FR2606869 which describes such a slipping driving band consisting of an underring, a front ring and a driving band body in two half-shells assembled by bolts or by hot forming. Such an arrangement is difficult to adapt to a medium or small caliber projectile. The assembly of a driving band body from two bolted half-shells is costly and delicate to effect on small parts. If assembly involves hot forming a band using a plastic material, the residual clearance obtained after cooling is difficult to reproduce.
U.S. Pat. No. 3834314 provides for the discarding sabot projectile being fitted with a driving band which, under the gas pressure, slides on a tapered section, the angle of which is open towards the front of the projectile. Sliding has the result of compressing the ring between the tapered sabot and the rifling of the weapon barrel and provides the desired seal although to the detriment of suitable sliding of the band on the projectile.